The goal of this R21 project is develop novel approaches to identify inhibitors of Mycobacterium tuberculosis that will have potent in vivo activity. The hypothesis underlying this proposal is that inhibitors that have increased activity i the setting of oxidative or nitrosative stress will be active during human infection, where these stresses are generated by host phagocytes and function as major antibacterial effectors. The goal of this research will be addressed through two specific aims. First we will develop and perform small molecule screens to identify inhibitors that are active in the presence of oxidative or nitrosative stresses. Second, to examine whether stress-potentiated inhibitors are likely to be active in vivo, we will determine their activity in a human in vitro granuloma model of M. tuberculosis infection. Completion of these aims will provide evidence as to whether inhibitors that are active in the presence of stress, or potentiated by stress, are likely to be good candidates for new anti-tuberculosis drugs. These data will provide the basis for performing large-scale stress- based screens to identify inhibitors that may be developed as candidate new drugs for tuberculosis.